Can't implement Yahoo BOSS v2 with OAuth in .net/C#

Hello,

I've been trying to create a simple search page using the Yahoo BOSS v2 api, but cant get OAuth to work properly. I have all the keys etc, and downloaded a C# class for OAuth at http://oauth.googlecode.com/svn/code/csharp/OAuthBase.cs , but I keep getting errors.

We've tried the following:

a javascript function builds a yahoo boss query string and then leads to
PageMethods.getYahoo(query string, responseFunction);

Here's the code behind

[WebMethod]
public static string getYahoo(string url)
{
String result;
OAuthBase oauth = new OAuthBase();
Uri uri = new Uri("http://mysite.com");
string a, qstring = "";
string signature = oauth.GenerateSignature(uri, "<my consumer key>", "<my
secret>", out a, out qstring);
url = url.Replace("{oauth}", qstring + "oauth_signature=" + signature);
WebResponse objResponse;
WebRequest objRequest = System.Net.HttpWebRequest.Create(url);
objResponse = objRequest.GetResponse();
using (StreamReader sr =
new StreamReader(objResponse.GetResponseStream()))
{
result = sr.ReadToEnd();
sr.Close();
}

return result;

}

here is my GenerateSignature method in oAuthBase class:

public string GenerateSignature(Uri url, string consumerKey, string
consumerSecret, out string normalizedUrl, out string
normalizedRequestParameters)
{
normalizedUrl = null;
normalizedRequestParameters = null;

string signatureBase = GenerateSignatureBase(url, consumerKey,null
,null,null,GenerateTimeStamp(),GenerateNonce(), HMACSHA1SignatureType, out
normalizedUrl, out normalizedRequestParameters);

HMACSHA1 hmacsha1 = new HMACSHA1();
hmacsha1.Key = Encoding.ASCII.GetBytes(string.Format("{0}&{1}",
UrlEncode(consumerSecret), ""));

return GenerateSignatureUsingHash(signatureBase, hmacsha1);

}


But we keep getting the error:

Message: Sys.Net.WebServiceFailedException: The server method 'getYahoo' failed
with the following error: System.Net.WebException-- The remote server returned
an error: (401) Unauthorized.
Line: 6934
Char: 21
Code: 0